Fluid delivery valve system and method

ABSTRACT

A method of forming a valve assembly for delivering a fluid from a fluid bag to an animal caging system for housing an animal can include injection molding an upper member having a piercing member and injection molding a sealing member. The upper member has a fluid channel defined therethrough and forms, in an injection molding machine, a unitary member with the sealing member. The method can also include injection molding a base having a flange member and a base fluid channel defined therethrough. The base is designed to be matingly coupled to the upper member. The method can further include injection molding a stem member constructed and arranged to be disposed in part within the base fluid channel. The stem member has an actuation portion extending through a spring element. The stem member has a top portion having a lower surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Patent Application of pending U.S.patent application Ser. No. 10/824,224 filed Apr. 13, 2004 and entitled“Fluid Delivery Valve System and Method” which is a Continuation-In-Partof U.S. application Ser. No. 10/274,619, filed on Oct. 21, 2002 andentitled “Fluid Delivery System” issued as U.S. Pat. No. 6,941,893 onSep. 13, 2005, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/346,218, filed on Oct. 19, 2001, the contents ofboth being incorporated in entirety by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to fluid delivery systems and inparticular to a fluid delivery system and method for caging or storagesystems for animals.

2. Description of Related Art

A large number of laboratory animals are used every year in experimentalresearch. These animals range in size from mice to non-human primates.To conduct valid and reliable experiments, researchers must be assuredthat their animals are protected from pathogens and microbialcontaminants that will affect test results and conclusions. Properhousing and management of animal facilities are essential to animalwell-being, to the quality of research data and teaching or testingprograms in which animals are used, and to the health and safety ofpersonnel.

Ordinarily, animals should have access to potable, uncontaminateddrinking water or other needed nutrient containing fluids according totheir particular requirements. Water quality and the definition ofpotable water can vary with locality. Periodic monitoring for pH,hardness, and microbial or chemical contamination might be necessary toensure that water quality is acceptable, particularly for use in studiesin which normal components of water in a given locality can influencethe results obtained. Water can be treated or purified to minimize oreliminate contamination when protocols require highly purified water.The selection of water treatments should be carefully considered becausemany forms of water treatment have the potential to cause physiologicalterations, changes in microflora, or effects on experimental results.For example, chlorination of the water supply can be useful for somespecies but toxic to others.

Because the conditions of housing and husbandry affect animal andoccupational health and safety as well as data variability, and effectan animal's well-being, the present invention relates to providing anon-contaminated, replaceable, disposable source of fluid for laboratoryanimals in a cage level barrier-type cage or integrated cage and racksystem to permit optimum environmental conditions and animal comfort.

Animal suppliers around the world have experienced an unprecedenteddemand for defined pathogen-free animals, and are now committed to theproduction and accessibility of such animals to researchers. Likewise,laboratory animal cage manufacturers have developed many caging systemsthat provide techniques and equipment to insure a pathogen freeenvironment. For example, ventilated cage and rack systems are wellknown in the art. One such ventilated cage and rack system is disclosedin U.S. Pat. No. 4,989,545, the contents of which are incorporatedherein by reference, assigned to Lab Products, Inc., in which an openrack system including a plurality of shelves, each formed as an airplenum, is provided. A ventilation system is connected to the racksystem for ventilating each cage in the rack, and the animals therein,thereby eliminating the need for a cage that may be easily contaminatedwith pathogens, allergens, unwanted pheromones, or other hazardousfumes. It is known to house rats, for example, for study in such aventilated cage and rack system.

The increasing need for improvement and technological advancement forefficiently, safely housing and maintaining laboratory animals arisesmainly from contemporary interests in creating a pathogen-freelaboratory animal environment and through the use of immuno-compromised,immuno-deficient, transgenic and induced mutant (“knockout”) animals.Transgenic technologies, which are rapidly expanding, provide most ofthe animal populations for modeling molecular biology applications.Transgenic animals account for the continuous success of modeling miceand rats for human diseases, models of disease treatment and preventionand by advances in knowledge concerning developmental genetics. Also,the development of new immuno-deficient models has seen tremendousadvances in recent years due to the creation of gene-targeted modelsusing knockout technology. Thus, the desire for an uncontaminated cageenvironment and the increasing use of immuno-compromised animals (i.e.,SCID mice) has greatly increased the need for pathogen free sources offood and water. One of the chief means through which pathogens can beintroduced into an otherwise isolated animal caging environment isthrough the contaminated food or water sources provided to theanimal(s).

Accordingly, the need exists to improve and better maintain the healthof research animals through improving both specialized caging equipmentand the water delivery apparatus for a given cage. Related caging systemtechnologies for water or fluid delivery have certain deficiencies suchas risks of contamination, bio-containment requirements, DNA hazardousissues, gene transfer technologies disease induction, allergen exposurein the workplace and animal welfare issues.

Presently, laboratories or other facilities provide fluid to theiranimals in bottles or other containers that must be removed from thecage, disassembled, cleaned, sterilized, reassembled, and placed back inthe cage. Additionally, a large quantity of fluid bottles or containersmust be stored by the labs based on the possible future needs of thelab, and/or differing requirements based on the types of animalsstudied. This massive storage, cleaning and sterilization effort,typically performed on a weekly basis, requires large amounts of time,space and human resources to perform these repetitive, and often tedioustasks.

As such, a need exists for an improved system for delivering fluid tolaboratory animals living in cage level barrier-type rack and cagesystems.

SUMMARY OF THE INVENTION

The present invention satisfies this need, briefly stated, in accordancewith an embodiment of the invention, a fluid delivery system fordelivering a fluid to an animal caging system for housing an animal isdescribed. The fluid delivery system may comprise a fluid delivery valveassembly adapted to be coupled to a fluid bag holding a fluid. Byadvantageously using sanitized fluid bags, that may be disposable, theinvention may minimize the need for the use of fluid bottles thattypically must be removed from cages, cleaned, and sanitized on afrequent basis.

The delivery system may be utilized in a single cage or in multiplescages integrated into ventilated cage and rack systems known in the art.An embodiment of the invention described herein provides for a fluiddelivery system for delivering a fluid from a fluid bag to an animalcaging system for housing an animal and may comprise a fluid deliveryvalve assembly, wherein the fluid delivery valve assembly is adapted tobe coupled to the fluid bag to facilitate the providing of the fluid toan animal in the caging system. The fluid delivery valve assembly mayfurther comprise an upper member having a piercing member and aconnecting member, the upper member having a fluid channel definedtherethrough, a base having a flange member and a base fluid channeldefined therethrough, wherein the base is designed to be matinglycoupled to the upper member. The fluid delivery valve assembly mayfurther comprise a spring element disposed within the base fluid channeland a stem member disposed in part within the base fluid channel,wherein a portion of the spring element abuts the stem member to apply abiasing force.

Another embodiment is directed to a method of forming a valve assemblyfor delivering a fluid from a fluid bag to an animal caging system forhousing an animal can include forming, in an injection molding machine,an upper member having a piercing member and a connecting member. Theupper member has a fluid channel defined therethrough; and forms, in aninjection molding machine, a base having a flange member and a basefluid channel defined therethrough. The base is designed to be matinglycoupled to the upper member. The method can further include forming, inan injection molding machine, a stem member designed and dimensioned tobe disposed in part within the base fluid channel. The stem member hasan actuation portion extending through a spring element. The stem memberhas a top portion having a lower surface.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

Other features and advantages of this invention will become apparent inthe following detailed description of exemplary embodiments of thisinvention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing figures, which are merely illustrative, and wherein likereference characters denote similar elements throughout the severalviews:

FIG. 1 is an exploded perspective view of a fluid delivery systemincorporated into an animal cage assembly;

FIG. 2 is an exploded perspective view of a fluid delivery system anddiet delivery system in accordance with the present invention;

FIG. 3 is an exploded perspective view of an embodiment of a fluiddelivery valve assembly in accordance with the present invention;

FIG. 4 is a side view of the fluid delivery valve assembly of FIG. 3;

FIG. 5 is a side cutaway view of the upper member of the fluid deliveryvalve assembly of FIG. 3;

FIG. 6 is a perspective view of trigger assembly of a fluid deliveryvalve assembly in accordance with the present invention;

FIG. 7 is a top plain view of cup element in accordance with the presentinvention;

FIG. 8 is a perspective view of the cup element in accordance with thepresent invention;

FIG. 9 is a cutaway view of cup element in accordance with the presentinvention;

FIG. 10 is a perspective view of a diet delivery system;

FIG. 11 is a top plan view of diet delivery system incorporating a fluiddelivery system in accordance with the present invention;

FIG. 12 is a front cutaway view of diet delivery system;

FIG. 13 is a bottom view of a fluid bag in accordance with the presentinvention;

FIG. 14 is a perspective view of a fluid bag and a fluid diet componentwith a fluid delivery system in accordance with the present invention;

FIG. 15 is a cutaway view of a fluid bag in accordance with the presentinvention;

FIG. 16 is a side perspective view of an upper member of a fluiddelivery valve assembly including a support in accordance with thepresent invention;

FIG. 17 is a plain side view of a double-sided rack system incorporatingan animal cage;

FIG. 18 is an exploded perspective view of an embodiment of a fluiddelivery valve assembly in accordance with the present invention;

FIG. 19 is a side cutaway view of the fluid delivery valve assembly ofFIG. 18;

FIG. 20 is a perspective view of the stem of the fluid delivery valveassembly of FIG. 18;

FIG. 21 is a side cutaway view of the fluid delivery valve assembly ofFIG. 18, showing the stem in the sealed position;

FIG. 22 is a side cutaway view of the fluid delivery valve assembly ofFIG. 18, showing the stem in the opened position;

FIG. 23 is a side cutaway view of the fluid delivery valve assembly ofFIG. 18, showing the extension portion protecting the stem;

FIG. 24 is a side cutaway view of an upper member of a fluid deliveryvalve assembly including a wrapper in accordance with the presentinvention;

FIG. 25 is a side cutaway view of an upper member of a fluid deliveryvalve assembly including a disposable cap in accordance with the presentinvention;

FIG. 26 is a fluid bag filling and sealing device in accordance with thepresent invention;

FIG. 27 is a view of a fluid bag preparation room in accordance with thepresent invention;

FIG. 28 is another view of a fluid bag preparation room in accordancewith the present invention;

FIG. 29 is another view of a fluid bag preparation room in accordancewith the present invention;

FIG. 30 is a side cutaway view of an exemplary embodiment of a fluiddelivery valve assembly;

FIG. 31 is a side cutaway view of an exemplary embodiment of a stem of afluid delivery valve assembly;

FIG. 32 is an exemplary representational side view of a spring memberfor a fluid delivery valve assembly;

FIG. 33 is an exemplary schematic diagram of an injection moldingmachine for forming portions of a fluid delivery valve assembly;

FIG. 34 is a plan view of an exemplary mold for injection moldingcomponents of a fluid delivery valve assembly;

FIG. 35 is a cross-sectional elevational view of the mold of FIG. 34;and

FIG. 36 is an exemplary flow diagram illustrating portions of a processfor multi-step injection molding parts of a fluid delivery valveassembly.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference is made to FIGS. 1 and 2, wherein an animal cage assembly 90,which incorporates fluid delivery valve assembly 1, is shown. Cageassembly 90 incorporates a filter retainer 91, a filter frame 92, afilter top lock 93, a chew shield 94, a plurality of snap rivets 95, afluid bag 60 containing fluid 70, a fluid delivery valve assembly 1, adiet delivery system 96 providing support member 50, a chow receptacle111, a fluid bag receptacle 110, and a cage body 98. Cage body 98comprises a box-like animal cage with a combination diet delivery system96 capable of providing both food and fluid to animals within cageassembly 90. A filter 99 is also generally provided with cage assembly90 sandwiched between filter retainer 91 and filter frame 92. Cage body98 is formed with integral side walls 100, a bottom wall or floor 101and an open top end. The open top of cage body 98 is bordered byperipheral lip 102, which extends continuously there around. Cage body98 may also include a plurality of corner stacking tabs 103 forfacilitating stacking and nesting of a plurality of cage bodies 98.

Reference is made to FIGS. 3-5 wherein fluid delivery valve assembly 1is depicted. Fluid delivery valve assembly 1 includes an upper member10, a spring element 20, a trigger assembly 30, and a cup element 40 foruse in animal cage 90. Water delivery system 1 is held in place inanimal cage 90 by support element 50. Support element 50 extends fromdiet delivery system 96 and forms a floor for fluid bag receptacle 110.Alternatively, water delivery system 1 may be molded into diet deliverysystem 96.

As shown in FIGS. 4 and 5, upper member 10 includes piercing member 11,core member 12 and flange member 13. Upper member 10 also defines fluidchannel 14. Arrow “A” defines the flow of fluid through fluid deliveryvalve assembly 1 to trigger assembly 30 where fluid flow can be actuatedby an animal in animal cage 90. Piercing member 11 has a beveled tip 15at its upper end, the upper edge of which presents a sharp piercing edge16 that can come in contact and pierce fluid bag 60, releasing fluid 70in fluid bag 60 through fluid channel 14. Flange member 13 extends fromcore member 12. In a preferred embodiment, flange member 13 is circularin dimension. However, it will be readily understood by one of ordinaryskill in the art that flange member 13 may be any shape desired,provided however, that at least a portion of flange member 13 is widerin diameter than fluid channel 14 of core member 12. As shown in FIG. 3,spring element 20 may be a tightly wound coiled member which rests atoptip 35 of upper end 33 of stem 31 and enters upper member 10 throughfluid channel 14. As shown in FIG. 5, fluid channel 14 is dimensionedsuch that its upper extent within piercing member 11 is narrowed atposition 17 such that it prevents spring element 20 from exiting fluidchannel 14 through piercing member 11.

Reference is made to FIG. 6, wherein trigger assembly 30 is depicted.Trigger assembly 30 includes a stem 31, inserted through sealing member32. Stem 31 having an upper end 33 and a lower end 36. Lower end 36 ofstem 31 is substantially flat. Upper end 33 of stem 31 is generallyconical in shape, although other shapes may be used. Sealing member 32fits tightly around stem 31 thereby allowing limited movement aroundstem 31. Sealing member 32 is dimensioned such that the base of theconical portion of upper end 33 rests on it. Sealing member 32 is formedof a resilient material, such as rubber, silicone rubber, or any otherpliant malleable material. In a preferred embodiment, sealing member 32is made of a material that is not deleterious to mammals.

Cup element 40 is depicted in FIGS. 7-9. Cup element 40 has a base 43,an inner surface 41, and an outer surface 42. Base 43 also definesactuation channel 400. Lower end 36 of stem 31 of trigger assembly 30extends through actuation channel 400 towards the interior of animalcage 90. Fluid channel 14 extends from piercing edge 16 through piercingmember 11, core member 12 and spring element 20. Fluid channel 14terminates at the bottom wall of cup element 40. Trigger assembly 30extends through actuation channel 400. Cup element 40 has friction fitwith core member 12 of upper member 10 directly below flange member 13.

Diet delivery system 96, which houses fluid bag receptacle 110 and chowreceptacle 111 is shown in FIGS. 10-12. As shown in FIG. 11, fluid bagreceptacle 110 holds fluid bag 60 containing fluid 70. Fluid deliveryvalve assembly 1 is held securely in receptacle base 112 of fluid bagreceptacle 110 by the interconnection between flange members 13 a, 13 b,13 c and 13 d and locking members 51 a, 51 b, 51 c and 5 id. Piercingedge 16 of fluid delivery valve assembly 1 punctures fluid bag 60. Asshown in FIGS. 11 and 12, chow receptacle 111 of diet delivery system 96holds wire food holder element 116. A further embodiment of the presentinvention in shown in FIGS. 10 and 12, wherein fluid bag receptacle 110may be molded 110′ in order to facilitate the emptying of fluid 70contained in fluid bag 60 by fluid delivery valve assembly 1 and toprevent the animal from gaining purchase on the fluid bag receptacle. Inan alternate embodiment, fluid bag 60 is tapered or dimensioned so as tofacilitate the emptying of fluid bag 60 by fluid delivery valve assembly1. Fluid bag 60 may be made replaceable or disposable and thus may bemanufactured singly in any quantity according to the needs of a user.

Fluid delivery valve assembly 1 may be used to deliver the contents offluid bag 60 to an animal in cage assembly 90. Fluid 70 in fluid bag 60may include water, distilled water, water supplemented with variousvitamins, minerals, medications such as antibiotics or anti-fungalagents, and/or other nutrients, or any fluid which is ingestible by acaged animal. Fluid 70 in fluid bag 60 is delivered to an animal in cageassembly 90 in a sterilized or sanitized condition so as to protect anyanimals in cage assembly 90 from contagion. Fluid bag 60 may be formedin any desirable shape or volume. In a preferred embodiment, fluid bag60 is formed to fit fluid bag receptacle 110.

Also, it should be clear that fluid bag 60 does not have to consist of aflexible material but that part thereof may be made of a rigid material.In an embodiment of the present invention, fluid bag 60 would consist ofone or more layers, which would tear upon insertion of piercing member11. Alternatively, flexible, stretchable, resilient plastic stickers 501may be provided which can be adhered to the bag to prevent tearingthereof and to form a seal about the inserted piercing member 11. Inaddition, as depicted in FIGS. 13-15, fluid bag 60 could be made of athinner plastic or inverted in the region where piercing edge 16 willpenetrate fluid bag 60, thereby allowing the end user to readilyidentify where fluid bag 60 should be punctured and helping fluid bag 60nest within fluid bag receptacle 110. In a further embodiment of thepresent invention, fluid bag 60 could be made of a resilient plastic orpolymer material such that when piercing edge 16 penetrates fluid bag 60at location 88, fluid bag 60 adheres to piercing member 16 so as to stopfluid 70 from leaking out of fluid bag 60. Fluid bag 60 may beconstructed out of any material which is capable of being punctured bypiercing member 16 and which is capable of holding fluid in a sterilizedcondition. In an embodiment of the invention, fluid bag 60 is plastic orany other flexible material capable of containing a fluid to bedelivered to one or more laboratory animals. In a further embodiment ofthe present invention, fluid delivery valve assembly 1, upper member 10,fluid bag 60 and the contents thereof, fluid 70, are capable of beingsterilized by one or more of an assortment of different means includingbut not being limited to: ultraviolet light, irradiation, chemicaltreatment, reverse osmosis, gas sterilization, steam sterilization,filtration, autoclave, and/or distillation. Each of the elements of thecurrent invention, fluid delivery valve assembly 1, fluid bag 60 andfluid 70, can be sterilized or sanitized alone or in combination witheach other. Fluid 70 of fluid bag 60 may be sterilized either before orafter fluid bag 60 is sealed.

In one embodiment providing a method of sterilization for the contentsof fluid bag 60, a chemical compound capable of sterilizing the fluid70, and known in the art, is put inside fluid bag 60 with fluid 70 priorto fluid bag 60 being sealed. Thereafter the compound sterilizes fluid70 such that it can be delivered to an animal and consumed by thatanimal without harm. Other methods of sterilization are discussed below.

In an embodiment of the invention, leak preventing member 501 is affixedor formed to upper member 10 and prevents a loss of fluid 70 from fluidbag 60 after puncture by piercing member 11.

As shown in FIG. 14, piercing member 11 may be rigidly fixed to supportelement 50 of fluid bag receptacle 110 (see FIGS. 1 and 4), inparticular in the support for the bag having its point directed upwardsso that piercing member 11 is automatically inserted into fluid bag 60at location 88 when placing fluid bag 60 onto support element 50 or intofluid bag receptacle 110′.

In one embodiment of the present invention, fluid bag 60 is placed influid bag receptacle 110 of animal cage 90. Fluid bag receptacle 110 hasa base 112, an inner surface 114 and an outer surface 115. Receptaclebase 112 also defines actuation channel 400. When fluid delivery valveassembly 1 is used in conjunction with animal cage 90, stem 31 oftrigger assembly 30 extends through cup 40 towards the interior ofanimal cage 90. In another embodiment, that portion of receptacle base112 which encircles actuation channel 400 may include one or morelocking members 51.

As shown in FIG. 16, in an alternate embodiment, support member 50 mayhave four (or some other number of) locking members 51 a, 51 b, 51 c and51 d formed thereon which may be used to secure flange members 13 a, 13b, 13 c and 13 d to support member 50. It will be readily understood byone of ordinary skill in the art that flange members 13 a, 13 b, 13 cand 13 d may vary in shape, provided however, that flange members 13 a,13 b, 13 c and 13 d are secured in fluid receptacle base 112 or ontosupport member 50 by its locking members 51 a, 1 b, 51 c and 51 d. InFIG. 16, locking members 51 a, 51 b, 51 c and 5 id are shaped likefingers and flange member 13 is divided into four equal pieces, shown asflange members 13 a, 13 b (not shown), 13 c and 13 d.

Referring now to FIG. 17, an animal isolation and caging rack system 600of the invention includes an open rack 615 having a left side wall 625and a right side wall 630, a plurality of rack coupling stations 616, atop 635, and a bottom 640. A plurality of posts 645 are disposed inparallel between top 635 and bottom 640. Vertical posts 645 arepreferably narrow and may comprise walls extending substantially fromthe front of rack 615 to the rear of rack 615, or may each comprise twovertical members, one at or near the front of rack 615 and the other ator near the rear of rack 615. Animal isolation and caging rack system600 also includes a plurality of air supply plena 610 and air exhaustplena 620 alternately disposed in parallel between left side wall 625and right side wall 630 in rack 615.

The above discussed fluid delivery valve assembly 1, while facilitatingthe providing of fluid to animals, was found to have some deficiencieswhen used in conjunction with certain rack and cage systemconfigurations. For example, with reference back to FIG. 3, when thestem 31 of the trigger assembly 30 is actuated by an animal, undercertain circumstances, the stem may remain stuck in the open positioneven after the animal discontinues actuating the stem 31. If the stemremains stuck in the open position, fluid may continue to leak into thecage and cage bedding, with the result being a waste of fluid, and thepotential for the animal to become hypothermic, or otherwise adverselyaffected.

One reason for the occurrence of this problem in certain circumstancesmay be that due to the specific arrangement of the stem 31, sealingmember 32 and spring element 20 within the fluid channel 14, when thestem 31 is actuated by an animal, the pivot point of upper end 33 ofstem 31 about the bottom of spring element 20 tends not to be eitherpredictable or consistent. Consequently, after actuation by an animal,stem 31, in certain circumstances, will shift position in relation tospring element 20, thus not allowing spring element 20 to bias stem 31back into the desired closed position.

With reference to FIG. 18, there is shown a fluid delivery valveassembly 200 that overcomes the above-discussed deficiency because,among other modifications, the arrangement of stem member 240, springmember 250, and sealing member 260 is different than that of theirrespective corresponding parts in fluid delivery valve assembly 1. Thisarrangement of stem member 240, spring member 250, and sealing member260, discussed in detail below, provides for a predictable andconsistent pivot point for stem member 240, thus facilitating a moreconsistent return to the closed position in the absence of actuation byan animal.

Thus, fluid delivery valve assembly 200 is different in structure andarrangement to that of fluid delivery valve assembly 1 in severalrespects. However, in accordance with the present invention, fluiddelivery valve assembly 200 may be used in all embodiments discussedabove with reference to fluid delivery valve assembly 1. Accordingly, inany embodiment described herein that describes the use of fluid deliveryvalve assembly 1 in conjunction with, by way of non-limiting example,fluid bag 60, animal isolation and caging rack system 600, and/or dietdelivery system 96, fluid delivery valve assembly 200 may be used aswell, in accordance with the invention.

With reference again to FIG. 18, there is shown fluid delivery valveassembly 200 having an upper member 210, and a base 220. Fluid deliveryvalve assembly 200 also includes sealing member 260, stem member 240,and spring member 250.

Upper member 210 is formed with generally conical piercing member 211having sharp point 214 for piercing fluid bag 60 as described above. Oneor more fluid apertures 215 are defined in a portion of piercing member210, to facilitate the flow of fluid 70 from bag 60 into a fluid channel216 defined within the piercing member 210. Upper member 210 is alsoformed with connecting member 212, having gripping portion 213encircling a portion thereof.

Base 220, being generally cylindrical in shape, includes top portion 221and bottom portion 222, which are separated by flange member 226 whichencircles base 220 and extends outwardly therefrom. Flange member 226may be used to facilitate mounting or positioning of fluid deliveryvalve assembly 200 as is described above with regard to fluid deliveryvalve assembly 1. Top portion 221 may have an inner surface 223 withgripping portion 213 disposed thereon.

Upper member 210 is designed and dimensioned to be coupled to base 220with connecting member 212 being inserted into base top portion 221. Thecoupling may be facilitated by the frictional interaction of grippingportion 213 of upper member 210 with gripping portion 224 of base 220.

Sealing member 260, stem member 240, and spring member 250 are disposedwithin base fluid channel 230. Stem member 240 has a top portion 241that may be generally flat, such that flow aperture 265 of sealingmember 260 may be advantageously sealed when a portion of bottom surface262 of sealing member 260 is contacted by top surface 243 of stem member240. Actuation portion 242 of stem member 240 extends through springmember 250 and through base fluid channel 230. Spring member 250 servesto bias stem member 240 against sealing member 260 to facilitate controlof the flow of fluid, as described above with respect to fluid deliveryvalve assembly 1.

With reference to FIG. 19, spring member 250 is retained within basefluid channel 230 at its bottom end as fluid channel 230 has narrowportion 232, which serves to block spring member 250 from passingthrough and out of fluid channel 230. The top of spring member 250 abutsthe lower surface 244 (see FIG. 20) of stem member 240. Spring member250 serves to bias stem member 240 in a vertical orientation, thusforming a seal between top surface 243 and sealing member 260. This sealmay be facilitated by the use of lower ridge 266 to concentrate thebiasing force of spring member 250 to form a seal against stem member240.

Turning to FIGS. 21 and 22, there is shown the operation of fluiddelivery valve assembly 200 when stem member 240 is actuated by ananimal. It should be noted that spring member 250 is not shown in FIGS.21 and 22 for sake of clarity. During actuation of stem member 240 by ananimal, however, as discussed above, spring member 250 provides abiasing force to bias stem member 240 toward a generally verticalposition.

With reference to FIG. 21, stem member 240 is positioned generallyvertically, with top surface 243 of stem member 240 advantageouslyabutting lower ridge 266 of sealing member 260 at sealing point 246. Theuse of lower ridge 266 in conjunction with top surface 240advantageously serves to focus and concentrate the biasing force ofspring member 250 to form a seal as discussed above.

Fluid delivery system 200 is shown having been punctured into fluid bag60 such that fluid 70 may flow from fluid bag 60 into fluid aperture 215of upper member 210, and in turn flow into fluid channel 216, throughflow aperture 265 of sealing member 260, down to sealing point 246. Atthis point, with stem member 240 in the vertical (sealed) position, flowof the fluid is stopped.

In an embodiment of the invention, bag 60, once punctured by fluiddelivery valve assembly 200, should have its outer wall positioned inthe range along surface 235 of top portion 201 of base 220 such that itremains disposed in the portion delimited at its upper bounds by bagretention wall 217 and at its lower bounds by flange top surface 227. Inan embodiment of the invention, flow aperture 215 and (in someembodiments) aperture portion 218 may be advantageously positioned aboutan edge of bag retention wall 217.

Turning now to FIG. 22, there is shown stem member 240 positioned as itwould be while an animal actuates actuation portion 242 of stem member240 in a direction B. Of course, one skilled in the art would recognizethat the same result would be achieved so long as the stem member isactuated outwardly, out of its resting vertical position. Upon actuationin direction B, stem member 240 pivots about pivot point 236 such thattop surface 243 of stem member 240 moves away from the lower ridge 266of sealing member 260. This movement allows fluid 70 at flow aperture265 of sealing member 260 to flow down through gap 237, into fluidchannel 230, and out to the animal in the general direction A.

Base 220 may be formed with abutment wall 233 disposed in fluid channel230 such that the maximum travel of stem member 240 is limited such thatthe flow of fluid 70 is advantageously limited to a desired value.Additionally, stem member 240, base 220, sealing member 250 and springmember 250 may be advantageously designed and dimensioned such that stemmember 240 pivots at a consistent and predictable pivot point 236 andwill thus not be subject to sticking or jamming in the open positionafter stem member 240 is released from actuation by the animal.Consequently, the wasting of fluid and the exposure of animals tohypothermia or other problems caused by excessive wetting of the cageand bedding material may be minimized.

Turning to FIG. 23, embodiments of the invention may be formed with base220 of fluid delivery valve assembly 200 having extension portion 234.Extension portion 234 may serve, in certain application specificscenarios, to protect the actuation portion 242 of stem member 240 frombeing accidentally bumped by an animal, as only a portion of actuationportion 242 extends beyond extension portion 234. In an embodiment ofthe invention, the relative lengths L1 and L2 of extension portion 234and actuation portion 242 may be adjusted based on the results desired,and the types of animals being fed, as well as other factors.

Referring to FIG. 24, in an embodiment of the current invention waterdelivery system 1 (or fluid delivery valve assembly 200) is sterilizedand/or autoclaved and maintained in a sterilized state prior to use in awrapper 47 or other suitable container so as to avoid infecting ananimal in animal cage 90 (while, for sake of brevity, the embodiments ofthe invention discussed below make specific reference only to fluiddelivery valve assembly 1, it is to be understood that fluid deliveryvalve assembly 200 may also be used in all instances as well). When auser determines that a clean water delivery system is needed inconjunction with a fluid bag 60, water delivery system 1 is removed fromwrapper 47 in sterile conditions or utilizing non-contaminating methodsand inserted into animal cage 90 in fluid bag receptacle 110 (while itis contemplated that all of fluid delivery valve assembly 1 would becontained within wrapper 47, only a portion of fluid delivery valveassembly 1 is illustrated in FIG. 24). Thereafter fluid bag 60 is placedin fluid bag receptacle 110 and is punctured by piercing member 11 suchthat fluid 70 (i.e., water) is released through fluid channel 14 to ananimal in animal cage 90. This procedure insures that sterilized fluid70 is delivered through an uncontaminated fluid channel and that fluiddelivery valve assembly 1 is itself uncontaminated and pathogen free.Additionally, in an embodiment of the invention, fluid delivery valveassembly 1 may be sold and stored in blister packs in groups of variousquantities.

Referring to FIG. 25, in another embodiment of the invention the upperportion of fluid delivery valve assembly 1, including upper member 10and piercing member 11, is covered with a disposable cap 45, that can beremoved when a user wants to use water delivery system 1 to pierce fluidbag 60 and place it in fluid bag receptacle 110 for delivery of a fluidto an animal in animal cage 90. Disposable cap 45 can be made from anysuitable material and may be clear, color-coded to indicate the type offluid in fluid bag 60, clear or opaque. Disposable cap 45 is easilyremoved from fluid delivery valve assembly 1. While cap 45 would notprovide for a sterilized fluid delivery valve assembly 1, it wouldprovide a labeling function, as well as, in an embodiment, provideprotection from inadvertent stabbing of a user.

An embodiment of the present invention provides a system and method forfluid delivery to one or more animal cages. The system provided has atleast two methods of use, one which includes providing sealed sanitizedbags of fluid for use in an animal cage or caging system. The providerprovides the pre-packaged and uncontaminated fluid (e.g., water, orfluid with nutrients etc., as needed by an animal) for use preferably bydelivering sanitized, fluid-filled, bags to a site designated by a user.Alternatively, the provider may locate a sealing apparatus, material formaking the fluid bags and fluid supply at a location designated by theuser. Thereafter, the provider will assemble, fill and seal theappropriate number of fluid bags for a user at the designated location.In a second method the provider provides a sealing apparatus and thematerial for making the fluid bags to a user. In this second method theprovider may also supply any appropriate fluid to the user at a locationdesignated by the user. The user thereafter assembles, fills and sealsthe fluid bags for use in the fluid delivery system of the invention asappropriate.

A fluid bag filling and sealing method and system 300, in accordancewith an embodiment of the invention, is illustrated in FIG. 26. Bagmaterial 310, which may be formed of any suitable material as describedabove, is stored in bulk form, such as, for example, in roll form. Asthe process continues, bag material 310 is moved over bag formingportion 330 such that the generally flat shape of bag material 310 isformed into a tube. As the process continues, a vertical seal device 340forms a vertical seal in bag material 310, thus completing the formationof a tube.

Contents supply portion 320 serves to add ingredients, via, for example,gravity feed, into the tube of bag material 310. Contents supply portion320 may include liquid and powder storage containers, and various pumpsand other supply means, such that, for example, fluid 70, either with orwithout any additives as discussed above, may be added and metered outin appropriate quantities as is known in the art. Additionally, contentssupply portion 320 may include heating and/or sterilizing equipment suchthat the contents supplied from contents supply portion 320 are in agenerally sterilized condition.

Next, horizontal seal device 350 forms a horizontal seal, eitherthermally, by adhesives, or by some other art recognized method as wouldbe known to one skilled in the art. The horizontal seal serves toisolate the contents of the tube into separate portions. Next, the bagcutting device cuts the bag material at the horizontal seal to formindividual fluid bags 60 containing fluid 70.

Of course, in accordance with the spirit of the invention, the exactsteps taken to form the fluid bags 60 may be varied as a matter ofapplication specific design choice. In some embodiments of the inventionsteps may be added, left out, or performed in a different order.Additionally, the contents and bag material 310 of fluid bags 60 may besterilized either before or after the completed bags are formed.

In an embodiment of the invention, and with reference to FIGS. 27-29,the fluid 70 is heated to approximately 180° F., and the fluid bags arestacked in storage containers 370 with the result that the fluid 70,fluid bags 60 and storage containers all become sterilized to asatisfactory degree. In an embodiment of the invention, a cage body 98may be used as such a storage container. Additional parts of thisprocess may also be automated, as is shown by the use of robotic arm 380in stacking containers.

Storage containers 370 (or cage bodies 98) may also be supplied withfluid bags 60 at a workstation 382, before placement in a isolation andcaging rack system 600. Additionally, storage containers 370 (or cagebodies 98) may be passed through various other sterilizing devices.

With reference to FIG. 30, there is shown another embodiment of a fluiddelivery valve assembly 400, which, as can be seen, is similar in manyrespects to fluid delivery valve assembly 200, described above. Throughexperimentation, it was found that an actuation force of 3 grams or lesswas optimal for allowing animals to obtain fluid from the valve assembly400 efficiently and effectively. As described above with respect tofluid delivery valve assembly 200, the actuation force of actuating stemmember 440 is related to the length of actuation portion 442 of stemmember 440 (which acts as a lever as the top surface 443 of stem member440 pivots upon sealing member 460), and the characteristics of springmember 450, which applies biasing force against stem member 440. Toachieve this desired actuation force requirement, experiments wereperformed using various dimensions of the spring 460 (discussed below),base fluid channel 430, and stem member 440. Dimensions, for certainembodiments, were as follows: The width L3 of base fluid channel 430 wasdimensioned to be about 0.205 in. The length of base fluid channel L4(measured to the bottom of sealing member 460) was dimensioned beoptimal about 0.300 in.

With reference to FIG. 31, various dimensions with respect to stemmember 440 were found to be beneficial. For example, the width L5 of topsurface 443 of stem member 440 was dimensioned to be about 0.200 in. Thelength L6 of stem member 440 was dimensioned to be about 0.420 in. Theheight L7 of edge 445 of stem member 440 was dimensioned to be about0.030 in. The thickness L8 of extension 447 of stem member 440 wasdimensioned to be about 0.020 in. The depth L9 of stem cavity 446 wasdimensioned to be about 0.025 in. The width LI0 of stem cavity 446 wasdimensioned to be about 0.100 in. Finally, the width L11 of actuationportion 442 of stem member 440 was dimensioned to be about 0.062 in.

With reference to FIG. 32, there is illustrated an exemplary embodimentof spring member 450. Spring member 450 can be formed from 302 stainlesssteel wire with nickel coating, the wire having a diameter of 0.011 in.Outer diameter L13 can be about 0.188 in., and spring member 450 canhave a free length L12 (length with no applied force) of 0.350 in. Theload (or force generated by spring member 450) when compressed to alength of 0.255 in. (the approximate length of spring member 450 whenhoused within fluid delivery valve assembly 400) is 22.3 grams, within arange of plus or minus 3.5 grams. Of course, while certain embodimentshave components dimensioned within the above limits, other dimensionsmay also be used, in accordance with the teachings herein. In certainembodiments, spring member 450 can have a total of about 19.4 coils,with about 6.4 of the coils being active, and about 13.4 of the coilsbeing “dead coils.”

Active coils 451 are coils that are free to deflect under a load. Incontrast, a dead coil 452 is a coil of wire which does not contribute tothe motive force of a spring. Generally, in extension and torsionsprings, there are no dead coils. Typically, in compression springs,such as spring member 450, the coils at each end that lay against eachother are dead coils, with the rest being active coils. In certainembodiments, however, additional dead coils 452 are employed tofacilitate the assembly process. Specifically, because of the relativelysmall dimensions of spring member 450, the spring members 450 tend tonest and tangle when piled or grouped together as the active coils tendto become intertwined.

In certain embodiments, however, dead coils 452 are advantageouslyemployed to minimize the tangling of the spring members 450 duringstorage and assembly. In certain embodiments, groups 453 of dead coils452 are positioned at various locations on spring member 450. In oneembodiment, a group 453 of about 4.5 dead coils 453 is located at eachend of spring member 450 and another grouping 453 of 4.5 dead coils 452is located at the middle of spring member 450. Because the coils in thegroupings 453 of dead coils 452 are positioned close together, coilsfrom adjacent spring members 450 do not penetrate between the coils andthe spring members 450 are less likely to tangle when piled or storedprior to assembly in fluid delivery valve assembly 400. In addition, thecombination of spring member 450 dimensions described, in combinationwith the various dimensions described above with respect to stem member440 and base 420 have been found to provide for a valve with anactuation force of 3 grams or less.

To facilitate production of large quantities of fluid delivery valveassemblies 400, certain components, such as, for example, upper member410, base 420 stem member 440, and sealing member 460, can be formed byway of an injection molding process. Generally, injection molding is theprocess of forcing melted plastic into a mold cavity. Once the plastichas cooled, the part can be ejected. With this process, many parts canbe made at the same time, out of the same mold.

With reference to FIG. 33, an exemplary injection molding apparatus 500in accordance with certain embodiments is shown. In the injectionmolding process, resin 502 is fed to the apparatus through the hopper504. The resins enter the injection barrel 506 by gravity though thefeed throat 508. Upon entrance into the barrel 506, the resin 502 isheated by heating elements 510 to the appropriate melting temperature.

The resin 502 is injected into the mold 512 by a reciprocating screw 514or a ram injector. The reciprocating screw offers the advantage of beingable to inject a smaller percentage of the total shot (amount of meltedresin in the barrel). Typically, a screw 514 injector is better suitedfor producing smaller parts. The resin is moved through a runner to theoutlet, or gate, and then into the mold cavity. The gate provides theconnection between the runner and the molded part.

The mold 512 receives the plastic and shapes it appropriately. The moldis cooled to a temperature that allows the resin to solidify and be coolto the touch. The mold plates 514 are held together by hydraulic ormechanical force. After sufficient part cooling, the mold is opened andthe part 516 is ejected.

The characteristics of the injection molded part are affected by threemain categories of parameters: material parameters; geometry parameters;and manufacturing parameters. Material parameters include, among others,the viscosity of the material used and its associatedpressure-volume-temperature behavior. Relevant geometry parametersinclude, among others, the wall thickness of the part, the number ofgates from which the melted material passes into the mold, and thethickness of the gates. Some of the relevant manufacturing parametersinclude, among others, the mold temperature, the melt temperature of thematerial, and the pressure applied to the mold. The performance of aninjection-molded part is dependent on the interaction of these groups ofparameters, as would be understood by one of ordinary skill in the art,as instructed by the disclosure herein.

In addition, while an embodiment of fluid delivery valve assembly 200has been described herein as comprising a separate sealing member 260,and piercing member 210, these components can also be formed as a singlecomponent comprising sealing member 460 and upper member 410 integrallyformed as a single component. Such an integrally formed component may bemade by way of a multi-step molding process.

Multi-step molding (or two-shot molding) requires a machine with twoindependent injection units, each of which injects a different material.The first material is injected through a primary runner system by apiston, as in a typical injection molding cycle. During this injection,the mold volume to be occupied by the second material is shut off fromthe primary runner system. The second runner system is then connected tothe volume to be filled and the second material is injected. Aftersufficient part cooling, the mold is opened and the part is ejected.

With reference to FIGS. 34 and 35, there is shown in FIG. 34 a planview, and in FIG. 35, an elevation view of an exemplary mold 520 forintegrally formed upper member 410 and sealing member 460. The mold 520contains a plurality of cavities 522 in which the integral upper member410 and sealing member 460 can be formed. The mold 520 is heated to apredetermined temperature, and a first material, in certain embodiments,polypropylene, is injected through the primary runner system 524 and outthe primary gates 526 into the cavities 522 to form the upper member 410portion of the integral component.

Next, a cylinder at each cavity is retracted, thus opening a smallsecondary cavity 528 in the shape of sealing member 460. Next, a secondmaterial, in certain embodiments, silicone rubber, is injected through asecondary runner system into secondary cavity 528. As the materialscool, the upper member 410 and the sealing member 460 portion can, incertain embodiments, become chemically bonded. Next, the mold 520components are separated and the integrally formed upper member 410 andthe sealing member 460 components are ejected from the mold 520.

With reference to FIG. 36, portions of the multi-step molding process700 for the upper member 410 and sealing member 460 are described.First, the mold sections are closed. Step 710. Next, the first materialis injected into the primary cavity, forming the upper member 410portion. Step 720. Next, a cylinder is actuated and retracted, thuscreating a secondary cavity in the shape of sealing member 460. Step730. Next, the second material is injected into the newly formedsecondary cavity, thus forming the sealing member 460 portion. Step 740.The combined integral component is then allowed to cool, the first andsecond materials forming a chemical bond. Step 750. Finally, thecombined component is ejected from the mold.

Accordingly, by way of this multi-step injection molding process, theupper member 410 can be integrally formed with sealing member 460, thusresulting in one less separate component during the valve assemblyprocess. In certain embodiments, the base 420 and stem member 440 arealso formed by injection molding. In addition, by having sealing member460 integrally formed with upper member 410, the chances of sealingmember 460 being misaligned during the assembly process are greatlyminimized, thus providing for a larger amount of properly assembledvalves. Further, by forming components of fluid delivery valve assembly400 via injection molding, relatively large amounts of these componentsfluid delivery valve assemblies 400 can be produced, within precisiontolerances, and with a relatively low failure rate.

Moreover, a benefit of forming the fluid delivery valve assembly 400 byway of a multi-step injection molding process is that the fluid deliveryvalve assemblies 400 can be made relatively quickly, and inexpensively.In addition, the use of a spring having strategically place dead coils,thus preventing nesting of the springs during the manufacturing process,also contributes to the ability for the methods described herein toresult in the manufacturing of a relatively inexpensive valve.Accordingly, because the fluid delivery valve assembly 400 isinexpensive, it is thus disposable. As such, the benefits of adisposable valve, such as no need for washing before reuse (because thevalve assembly 400 is typically discarded after use), may be realized.

Thus, while there have been shown and described and pointed outfundamental novel features of the invention as applied to exemplaryembodiments thereof, it would be understood that various omissions andsubstitutions and changes in the form and details of the disclosedinvention may be made by those skilled in the art without departing fromthe spirit of the invention. It is intended that all matter contained inthe above description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention that, as amatter of language, might be said to fall there between.

1. A method of forming a valve assembly for delivering a fluid from afluid bag to an animal caging system for housing an animal, the methodcomprising: forming an upper member having a piercing member, the uppermember having a fluid channel defined therethrough; and injectionmolding a sealing member, so that the sealing member is secured to theupper member during the injection molding of the sealing member.
 2. Themethod of claim 1, comprising: injection molding a base having a basefluid channel defined therethrough, wherein the base is constructed andarranged to be matingly coupled to the upper member, and wherein thebase is constructed and arranged to receive the sealing member withinthe base fluid channel.
 3. The method of claim 1, comprising: injectionmolding a base having a base fluid channel defined therethrough; andinjection molding a stem member having an actuation portion and a topportion having a lower surface, wherein the stem member is constructedand arranged to be disposed at least partially within the base fluidchannel.
 4. The method of claim 3, wherein the sealing member comprisesa flow aperture and a sealing member bottom surface, the sealing memberbeing constructed and arranged to facilitate sealing of the flowaperture when the sealing member bottom surface abuts a top surface ofthe stem member.
 5. The method of claim 1, comprising: injection moldingthe upper member in a first step of a multi-step injection moldingprocess; and injection molding the sealing member in a second step ofthe multi-step injection molding process.
 6. The method of claim 1,wherein the upper member and the sealing member form a unitarystructure.
 7. The method of claim 1, wherein the upper member comprisespolypropylene.
 8. The method of claim 1, wherein the sealing membercomprises silicone rubber.
 9. The method of claim 2, comprisinginserting a portion of the upper member into the base.
 10. The method ofclaim 2, comprising inserting a portion of the upper member into thebase wherein the upper member is secured to the base via a friction fit.11. The method of claim 3, comprising disposing a part of the stemmember within the base fluid channel.
 12. The method of claim 3, furthercomprising: disposing a spring element within the base fluid channel;wherein a portion of the spring element abuts the lower surface to applya biasing force to the stem member.
 13. The method of claim 12, whereinthe spring element comprises at least one group of dead coils, therebyfacilitating prevention of tangling of a plurality of spring memberswhen the spring members are arranged during assembly.
 14. The method ofclaim 12, wherein the spring element comprises at least three groups ofdead coils, at least one of the groups being located at the center ofthe spring element, at least one of the groups being located at a firstend of the spring element, and at least one of the groups being locatedat a second end of the spring element, thereby facilitating preventionof tangling of a plurality of spring members when the spring members arearranged during assembly.
 15. The method of claim 4, comprisingdisposing a spring element within the base fluid channel, wherein aportion of the spring element abuts the lower surface to apply a biasingforce to the stem member; wherein the sealing member bottom surface hasa lower ridge extending therefrom, the lower ridge being constructed andarranged to facilitate the concentration of the biasing force from thespring element to seal the flow aperture.
 16. The method of claim 3,wherein the stem member is constructed and arranged to selectivelyfacilitate the flow of fluid when the actuation portion is pushed. 17.The method of claim 3, wherein the stem member is constructed andarranged to selectively facilitate the flow of fluid when the actuationportion is pushed with a force of less than or equal to 5 grams.
 18. Themethod of claim 3, wherein the stem member is constructed and arrangedto selectively facilitate the flow of fluid when the actuation portionis pushed with a force of less than or equal to 3 grams.
 19. The methodof claim 1, wherein the valve assembly is disposable.
 20. The method ofclaim 1, comprising: piercing a fluid bag with the piercing member tofacilitate the providing of fluid from a fluid bag to an animal.
 21. Themethod of claim 20, comprising: disposing of the valve assembly afterthe animal has consumed fluid from the fluid bag.
 22. The method ofclaim 4, further comprising: disposing a spring element within the basefluid channel; wherein a portion of the spring element abuts the lowersurface to apply a biasing force to the stem member.
 23. The method ofclaim 22, wherein the spring element comprises at least one group ofdead coils, thereby facilitating prevention of a tangling of a pluralityof spring members when the spring members are arranged during theassembly process.
 24. The method of claim 22, wherein the spring elementcomprises at least three groups of dead coils, at least one of thegroups being located at the center of the spring element, at least oneof the groups being located at a first end of the spring element, and atleast one of the groups being located at a second end of the springelement, thereby facilitating prevention of tangling of a plurality ofspring members when the spring members are arranged during assembly. 25.A method of assembling a valve assembly for delivering a fluid from afluid bag to an animal caging system for housing an animal, the methodcomprising: coupling an upper member having a piercing member to a basehaving a base fluid channel defined therethrough; disposing a stemmember at least partially within the base fluid channel, the stem memberhaving an actuation portion and a top portion having a lower surface;disposing a sealing member in the base fluid channel, the sealing memberhaving a flow aperture and a sealing member bottom surface, the sealingmember being constructed and arranged to facilitate sealing of the flowapertures when the sealing member bottom surface abuts a top surface ofthe stem member. disposing a spring element within the base fluidchannel, wherein a portion of the spring element abuts the lower surfaceto apply a biasing force to the stem member.
 26. The method of claim 25,comprising injection molding the sealing member, so that the sealingmember is secured to the upper member during the injection molding ofthe sealing member to form a unitary structure.
 27. The method of claim25, wherein the spring element comprises at least one group of deadcoils, thereby facilitating prevention of a tangling of a plurality ofspring members when the spring members are arranged during the assemblyprocess.
 28. The method of claim 25, wherein the spring elementcomprises at least three groups of dead coils, at least one of thegroups being located at the center of the spring element, at least oneof the groups being located at a first end of the spring element, and atleast one of the groups being located at a second end of the springelement.
 29. The method of claim 25 wherein the sealing member bottomsurface has a lower ridge extending therefrom, the lower ridge beingconstructed and arranged to facilitate the concentration of the biasingforce from the spring member to seal the flow aperture.
 30. The methodof claim 25, wherein the stem member is constructed and arranged toselectively facilitate the flow of the fluid when the actuation portionis pushed.
 31. The method of claim 25, wherein the stem member isconstructed and arranged to selectively facilitate the flow of the fluidwhen the actuation portion is pushed with a force of less than or equalto 5 grams.
 32. The method of claim 25, wherein the stem member isconstructed and arranged to selectively facilitate the flow of the fluidwhen the actuation portion is pushed with a force of less than or equalto 3 grams.
 33. A method of forming a valve assembly for delivering afluid from a fluid bag to an animal caging system for housing an animal,the method comprising: injection molding an upper member having apiercing member, the upper member having a fluid channel definedtherethrough; injection molding a base having a base fluid channeldefined therethrough, wherein the base is constructed and arranged to bematingly coupled to the upper member; injection molding a sealing memberconstructed and arranged to be disposed within the base fluid channel,wherein the sealing member contacts the upper member.
 34. The method ofclaim 33, wherein the sealing member is secured to the upper memberduring the injection molding of the sealing member to form a unitarystructure.